A minor change for an obvous problem caused by r188451:
        def imm0_63 : Operand<i32>, ImmLeaf<i32, [{ return Imm >= 0 && Imm < 63;}]>{
As it seems Imm <63 should be Imm <= 63. ImmLeaf is used in pattern match, but there is already a function check the shift amount range, so just remove ImmLeaf. Also add a test to check 63.